Light emitting diode structure with high heat dissipation

ABSTRACT

A light emitting diode structure with a high heat dissipating effect includes a lead frame, a chip, two lead wires, an internal casing and an external casing. The lead frame has a first electrode and a second electrode, and the first electrode forms a cavity for installing the visible or invisible light chip in the cavity, and the chip is electrically coupled to two lead wires, and an end of the two lead wires is electrically and respectively coupled to the first and second electrodes, and the chip has an internal casing, and the two lead wires of the lead frame and the surface of the internal casing are wrapped by an external casing having a base and a lens.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light emitting diode, and more particular to a light emitting diode with a high heat dissipating effect.

2. Description of Prior Art

Traditional light emitting diode (LED) gradually replaces traditional light bulb due to its compact size, low power consumption, and long life expectancy, and thus LEDs are used extensively in the different areas such as traffic lights, signal lights, flashlights, mobile phones, lamps and large outdoor billboards. Since the brightness of a single piece of light emitting diode is very limited, several pieces of light emitting diodes are combined to produce a high-brightness light source, but such arrangement causes more complicated manufacturing processes and incurs higher costs.

As a result, a high-power light emitting diode is introduced to the market, and the high-power light emitting diode can produce a super high brightness light source, and its application simply requires several light emitting diodes to achieve the brightness required for illuminations and displays. Since the high-power light emitting diode can produce a super high-brightness light source and its application also causes a very high heat source, therefore a heat sinking slug is usually combined with the high-power light emitting diode to guide and dissipate the heat source produced by the light emitting chip, so as to ensure a long life expectancy of the high-power light emitting diode.

U.S. Pat. No. 6,274,924 entitled “Surface mountable LED package” discloses a heat sinking slug combined with a high-power light emitting diode. In the manufacturing process of a light emitting diode in accordance with such patented technology, a metal frame is prepared first; a base filled with a plastic material is formed on the metal frame; a through hole is created at the center of the base for inserting a reflector cup on the heat sinking slug into the through hole, an insulating base is produced in the reflector cup, and a chip is mounted onto the base; a lead wire is bonded between the chip and the frame; and an optical lens is packaged onto the base.

When the light emitting chip in accordance with the foregoing patented technology is lit, the heat produced by the light emitting chip is dissipated from the heat sinking slug to achieve the heat dissipating effect, but this type of high-power light emitting diodes involves a complicated manufacturing process and many types of equipments, and thus the manufacture consumes much time, takes many steps, and incurs high costs.

SUMMARY OF THE INVENTION

In view of the foregoing shortcomings of the prior art, the inventor of the present invention based on years of experience in the related industry to conduct experiments and modifications, and finally developed a light emitting diode with a high heat dissipating effect by using simple equipment to overcome the shortcomings of the prior art and lower the manufacturing cost significantly.

Therefore, it is a primary objective of the present invention to provide a light emitting diode structure with high dissipating, and the structure comprises: a lead frame, a chip, two lead wires, an internal casing and an external casing. The lead frame has a first electrode and a second electrode, a carrying portion disposed on the first electrode, a cavity and a plurality of through holes disposed on the carrying portion, a lead coupled to an end of the carrying portion, a heat dissipating protrusion disposed on the back side of the carrying portion, a solder portion and a lead disposed on the second electrode, a plurality of through holes disposed on the solder portion for installing the visible or invisible light chip into a cavity of the first electrode, two lead wires electrically coupled to the chip, an end of the two lead wires respectively and electrically coupled to the lead frame, an internal casing formed on the chip, and an external casing having a base and a lens formed at the internal casing, the two lead wires and the lead frame.

BRIEF DESCRIPTION OF DRAWINGS

The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself however may be best understood by reference to the following detailed description of the invention, which describes certain exemplary embodiments of the invention, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a flow chart of a manufacturing procedure of a light emitting diode of the present invention;

FIG. 2 is a front view of a lead frame of the present invention;

FIG. 3 is a rear view of a lead frame of the present invention;

FIG. 4 is a schematic view of adhering a chip onto a lead frame of the present invention;

FIG. 5 is a schematic view of wire bonding a chip of the present invention;

FIG. 6 is a schematic view of packaging a casing of the present invention

FIG. 7 is a schematic view of applying the present invention; and

FIG. 8 is a schematic view of a light emitting diode of another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The technical characteristics, features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings. The drawings are provided for reference and illustration only, but not intended for limiting the present invention.

Referring to FIG. 1 for a flow chart of a manufacturing procedure of a light emitting diode of the present invention, the manufacturing procedure of a light emitting diode with a high heat dissipation effect comprises the steps of:

Step 10: preparing a thick metal;

Step 20: shaping the thick metal into a plurality of connected lead frames by an etching technology or a punching technology;

Step 30: fixing a visible or invisible light chip onto the lead frame by an adhesive to complete a chip bonding process, wherein the adhesive is either non-conductive or conductive (such as a silver paste or a thermal paste);

Step 40: soldering the two lead wires onto the chip, and then soldering the two lead wires with the lead frame to complete a wire bonding process;

Step 50: dispensing silicon onto the chip to protect the chip, and dispensing an epoxy compound on the surface of the silicon (such as the manufacture of yellow light emitting diodes) at the chip, adhesive, lead wire and lead frame, and if it is necessary to manufacture a white light emitting diode, a fluorescent colloid is dispensed onto the chip first, and then silicon is dispensed onto the fluorescent colloid, and finally the epoxy resin is dispensed onto silicon; and

Step 60: pressing the compound into cylindrical, hemispherical or square base and lens by a thermal compression technology to complete the manufacture of a light emitting diode.

Referring to FIGS. 2 and 3 for a front view and a rear view of a lead frame of the present invention respectively, a thick metal is etched and punched into a first electrode 11 and a second electrode 12, both coupled to a lead frame 1, and the first electrode 11 has a carrying portion 111, and the carrying portion 111 has a circular cavity 112 and a plurality of through holes 113, and an end of the carrying portion 111 is coupled to a lead 114, and the back side of the carrying portion 111 forms a circular heat dissipating protrusion 115, and the second electrode 12 forms a solder portion 121 and a lead 122, and the solder portion 121 has a plurality of through holes 123, and the through holes 113, 123 are provided for passing the compound of the casing through the through holes 113, 123 and securing the lead frame 11 during the thermal compressing process of the casing of the light emitting diode.

Referring to FIG. 4 for a schematic view of adhering a lead frame onto a chip, the chip bonding is performed for the lead frame 1, and an adhesive 2 is coated onto a cavity 112 of the first electrode 11, and then the visible or invisible light chip 3 is adhered into the cavity 112. The adhesive 2 is a non-conductive silver paste or thermal paste.

Referring to FIG. 5 for a schematic view of wire bonding a chip of the present invention, two lead wires 31, 32 are soldered onto the chip 3 after a chip bonding is performed for the first electrode 11 of the lead frame 1, and the two lead wires 31, 32 are respectively and electrically coupled to the carrying portion 111 of the first electrode 11 and the solder portion 121 of the second electrode 12, such that if the two lead wires 31, 32 are electrically conducted, the chip 3 will produce a light source. In FIG. 5, the chip 3 is a light emitting diode chip.

Referring to FIG. 6 for a schematic view of packaging a casing of the present invention, silicon is dispensed onto the chip 3 to form an internal casing 4 for protecting the chip 3 after the chip bonding and wire bonding are performed at the lead frame 1, and then an external casing 5 is covered onto the lead frame 1, chip 3 and lead wire 31, 32 and internal casing 4, wherein the external casing 5 is made of an epoxy compound. After a base 51 and a lens 52 are formed integrally by a thermal compression technology, a light emitting diode with a high heat dissipating effect is completed.

Referring to FIG. 7 for a schematic view of applying the present invention, the back sides of first and second electrodes 11, 12 of the lead frame 1 are exposed, after the external casing 5 is thermally pressed. After the light emitting diodes are soldered onto an aluminum board 6, the back sides of the first and second electrodes 11, 12 are in full contact with the aluminum board 6, so that when the light emitting diodes are lit, the heat produced by the light emitting diodes are conducted through the back sides of the first electrode 11 (including a heat dissipating protrusion 115) and the second electrode 12 to the aluminum board 6. Such arrangement can expedite the heat dissipation of the light emitting diodes to extend the life expectancy of the light emitting diodes.

Refer to FIG. 8 for a schematic view of a light emitting diode of another preferred embodiment of the present invention. If it is necessary to manufacture a white light emitting diode, a lead frame 1, a light chip 3 and lead wires 31, 32 are produced first, and then a fluorescent colloid is dispensed onto the chip 3 to form a fluorescent layer 7, and silicon is dispensed onto the fluorescent layer 7 to form an internal casing 4 for protecting the chip 3, and an external casing 5 is covered onto the lead frame 1, chip 3, lead wires 31, 32 and internal casing 4, wherein the external casing 5 is made of an epoxy compound, and the compound is used for integrally shaping a base 51 and a lens 52 by a thermal compression technology, so as to complete the manufacture of a light emitting diode with a high heat dissipating effect.

In view of the manufacturing flow described above, the light emitting diode of the invention comes with a simple structure, an easy manufacturing process, and easy-to-use equipments for lowering the manufacturing cost of the light emitting diode.

The present invention is illustrated with reference to the preferred embodiment and not intended to limit the patent scope of the present invention. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims. 

1. A light emitting diode structure with high heat dissipation, comprising: a lead frame, having a first electrode and a second electrode disposed thereon; a carrying portion disposed on the first electrode, a cavity disposed on a front side of the carrying portion; a first lead coupled to an end of the carrying portion; a heat dissipating protrusion disposed on a back side of the carrying portion and protruding from the back side of the carrying portion essentially in a normal direction thereof; a solder portion and a second formed on the second electrode; a chip, mounted onto the cavity; two lead wires, for electrically coupling the chip to the first and second electrodes; and an external casing, having a base for wrapping the carrying portion, the chip, the lead wire and the solder portion, and the base carrying a lens; thereby, back sides of the first and second electrodes are exposed after the external casing wraps the carrying portion, the chip, the lead wire and the solder portion. wherein the carrying portion is configured to transfer heat out of the external casing to an ambient environment via the heat dissipating protrusion.
 2. The structure of claim 1, wherein the lead frame is made of metal.
 3. (canceled)
 4. (canceled)
 5. The structure of claim 1, wherein the cavity and the chip are fixed by an adhesive, and the adhesive is an epoxy resin.
 6. The structure of claim 1, further comprising an internal casing for wrapping the chip, the internal casing being covered by the external casing.
 7. The structure of claim 1, wherein the heat dissipating protrusion is in a circular shape.
 8. The structure of claim 1, wherein the carrying portion and the solder portion respectively have a plurality of through holes formed thereon.
 9. The structure of claim 1, wherein the external casing is made of an epoxy compound.
 10. The structure of claim 1, wherein the chip is a light emitting diode chip.
 11. The structure of claim 1, further comprising a fluorescent layer included between the chip and the internal casing. 